PM10 refers to particles with an aerodynamic diameter of 10 microns or smaller. For comparison, the diameter of a human hair is about 50 to 100 microns. Exposure to PM10 aggravates a number of respiratory illnesses and may even cause early death in people with existing heart and lung disease. PM10 includes the subgroup of finer particles with aerodynamic diameter of 2.5 microns and smaller (PM2.5). These finer particles pose an increased health risk because they can deposit deep in the lung and contain substances that are particularly harmful to human health. PM is a mixture of substances that include elements such as carbon and metals; compounds such as nitrates, organic compounds, and sulfates; and complex mixtures such as diesel exhaust and soil. These substances may occur as solid particles or liquid droplets. Some particles are emitted directly into the atmosphere. Others, referred to as secondary particles, result from gases that are transformed into particles through physical and chemical processes in the atmosphere. Please consider joining one or more of the ARB's Particulate Matter-related e-lists.

WHAT'S NEW?

Technical Report on the Characterization of PM10 and PM2.5 in California
An assessment of PM10 and PM2.5 characteristics in each of Califronia's air districts within each air basin.

Implementation of Senate Bill SB656, Sher 2003
Information on activities regarding ARB and Air District measures to reduce PM.

ADDITIONAL INFORMATION

The following links take you to ARB's reports on the PM2.5 program and to additional information on PM10 and PM2.5 ambient air quality standards, air quality and emissions data, special studies, monitoring, health studies, planning, and control strategy development.

• Report on ARB's PM2.5 Program
  This report describes the major elements of ARB's PM2.5 program.
• Report on ARB's PM2.5 Monitoring Program
  The report provides the 2006 annual update on ARB's PM2.5 monitoring program.

• Ambient Air Quality Standards for PM10 and PM2.5
  Information on both the national and State Ambient Air Quality Standards for PM.
• Area Designations
  Area designation maps for the current national and State PM10 standards and information on area designation activities.

• California Air Quality Data
  • California Almanac of Emissions and Air Quality
    Provides a compendium of PM10, PM2.5, and PM2.5 precursor emissions and air quality data.
  • ADAM
    The interactive ADAM database allows users to review historical air quality data directly from ARB's ADAM air quality database.
  • AQMIS
    The interactive AQMIS database allows users to review real-time air quality data directly from ARB's AQMIS ambient air quality database.
• California Emissions Data
  Provides emissions data of directly emitted PM10 and PM2.5 and of gaseous precursors of secondary PM2.5.

• CRPAQS
  The California Regional PM10/PM2.5 Air Quality Study is a multi-year effort of meteorological and PM air quality monitoring, emission inventory development, data analysis, and air quality modeling. Field work consisted of 14 months of monitoring, between December 1999 and February 2001.

• PM Monitoring
  Descriptions of air quality monitoring programs for PM including sampling/monitoring, laboratory analysis, and quality assurance.
• California's Air Quality Monitoring Network
  Listing and description of ambient air quality air monitoring sites in California and the northern Baja California portion of Mexico. The monitoring sites in the network include instruments that measure ambient levels of gaseous and particulate air pollutants, and in some cases, meteorological parameters.
• PM2.5 Monitoring Network Design
  ARB, in partnership with California's air quality management districts, has developed a PM2.5 monitoring network to support and assess compliance with the PM2.5 ambient air quality standards; support the smoke management plan; assist in health effects studies and other ambient research activities; and assess regional haze.

• Health Research Program
  • Children's Health Study
    The Children's Health Study is the nation's first large-scale effort to explore the effects on school-aged children of long-term exposure to outdoor air pollution, including PM, in Southern California.
  • F.A.C.E.S.
    The Fresno Asthmatic Children's Environment Study is a large epidemiological study of the effects of air pollution on children with asthma. The overall goal is to determine the effects of different PM components, in combination with other ambient air pollutants, on the natural history of asthma in young children.
  • Fine and Ultrafine Particulate Matter Research
    Describes numerous research projects on PM2.5 (fine) and particles with aerodynamic diameter of less than 0.1microns (ultrafine).

• State Implementation Plan
  Provides access to selected State Implementation Plans (SIPs) required by the federal Clean Air Act, including plans in development and submitted plans.

• Diesel Risk Reduction Plan
  Information on ARB's comprehensive program to reduce PM emissions and resultant health risk from diesel-fueled engines and vehicles.

• Regional Haze
  U.S. EPA regulations require states to improve visibility in national parks and wilderness areas. California is working with other western states to understand and improve visibility.

• Smoke Management Program
  California's Smoke Management Program addresses potentially harmful smoke impacts from agricultural, forest, and range land management burning operations.